The present invention relates to an aperture grille used in a Trinitron brand color cathode-ray tube.
A related art Trinitron brand color cathode-ray tube includes a single electron gun for emitting RGB electron beams, a stripe phosphor screen, and an aperture grille as a color separating mechanism.
The aperture grille is provided in the cathode-ray tube so as to be opposed to the stripe phosphor screen provided on the inner surface of a front panel with a given space defined between the aperture grille and the phosphor screen, thereby leading the electron beams emitted from the electron gun to the phosphor screen.
FIG. 1 is a perspective view showing the configuration of such a related art aperture grille.
The aperture grille has a flat grille 10 formed with vertical stripes of slits 12 and line electrodes 14 by etching or the like of a soft steel sheet, and a steel frame member 20 to which the flat grille 10 is connected by welding or the like under a given tension.
The frame member 20 has a pair of first frames 22A and 22B connected to the vertical opposite ends of the flat grille 10 corresponding to the longitudinal opposite ends of the slits 12, and a pair of second frames 24A and 24B connected to the horizontal opposite ends of the first frames 22A and 22B so as to extend between the first frames 22A and 22B.
Two damper lines 16A and 16B are provided on the surface of the flat grille 10 so as to extend in a direction perpendicular to the slits 12.
The damper lines 16A and 16B function to suppress resonance of the flat grille 10 due to forced vibration by an external force. The damper lines 16A and 16B are supported under a given tension by two pairs of spring members 26 mounted on the second frames 24A and 24B, thereby keeping contact with the line electrodes 14 of the flat grille 10.
In the related art aperture grille mentioned above, however, the damper lines 16A and 16B are located on a substantially central portion of the flat grille 10 in respect of its vertical direction. Accordingly, a part of each of the damper lines 16A and 16B is located inside an effective screen region of the cathode-ray tube.
As a result, there is a possibility that the damper lines 16A and 16B may come into sight from the front side of the screen, thus marring the appearance of the screen.
It is accordingly an object of the present invention to provide an aperture grille which can suppress vibrations of the flat grille without marring the appearance of the screen by not locating the damper lines inside the effective screen region of the cathode-ray tube.
According to the present invention, there is provided in an aperture grille for a cathode-ray tube, having a flat grille as an electrode sheet formed with vertical stripes of slits and line electrodes, and a frame member to which said flat grille is connected under a given tension, the improvement comprising a damper member exposed to a region of said flat grille outside an effective screen region of said cathode-ray tube and kept in contact with said flat grille to suppress vibrations of said flat grille.
With the above configuration of the aperture grille according to the present invention, vibrations of the flat grille due to forced vibration by an external force can be suppressed by the damper member kept in contact with the flat grille, thus preventing resonance of the flat grille. Furthermore, the damper member is out of sight from the front side of the screen of the cathode-ray tube, because the damper member is provided in a region of the flat grille outside the effective screen region of the cathoderay tube. Accordingly, vibrations of the flat grille can be suppressed without marring the appearance of the screen.